D-Link SIP phone does not register


I am very new with this.

Got two D-Link DPH-150S and a Digium Asterisk AA50.

From default I created two user extensions tried all sorts of configs. Same on the D-Link phones, but cannot call the other extension.

Tried “sip set debug” cannot see anything there.

Strangly when I activate the on the Digium the voicemail function and i call the extension I can hear the message “The person at extension xxxx is not availagle”

any hint?

Finally the DPH-150S started registering. It is working fine with the AA50.

Though everything seems to be a bit slow… But I have no comparison if this is normal.

I have no clue what was the reason…